Fast curable epoxy compositions containing imidazole- and 1-(aminoalkyl) imidazole-isocyanate adducts
View Patent ↗Epoxy curing agents comprising imidazole-isocyanate adducts, including 1-(aminoalkyl)imidazole-isocyanate adducts and especially 1-(3-aminopropyl)imidazole-isocyanate adducts, and their use as curing agents in heat curable one-component epoxy resin compositions. Epoxy curing agents comprising imidazole-isocyanate adducts comprising the reaction product of at least one imidazole, at least one polyisocyanate and at least one diamine.
1. A curable epoxy composition comprising the contact product of at least one epoxy resin and an epoxy curing agent comprising an imidazole-isocyanate adduct which comprises a reaction product of at least one imidazole, at least one diamine, and at least one member selected from the group consisting of at least one polymethylene diisocyanate having 2-8 methylene units and at least one polymethylene poly(phenylisocyanate); wherein the imidazole-isocyanate adduct comprises an adduct represented by formula A:
where Z is (CH 2 ) n —NH, p is 0-1 and n is 3-8, R is the polyvalent residue of polymethylene poly(phenylisocyanate) having an isocyanate functionality of 2.1-3.5; and R 1 and R 2 independently represent hydrogen, C1-C20 linear or branched alkyl, C6-C10 aryl, alkylaryl or arylalkyl; or C5-C6 cycloaliphatic.
2. The epoxy composition of claim 1 which is a 100% solids epoxy composition.
3. The epoxy composition of claim 1 which is an aqueous epoxy composition of 20 to 80 wt % solids.
4. The epoxy composition of claim 1 further comprising at least one accelerator.
5. A method for providing a fast cure profile in an epoxy composition which comprises heating and curing an epoxy composition of claim 4 in which the difference between the beginning (Ti) and end (Tf) of the exotherm is less than 70° C. as determined by DSC analysis.
6. A method for providing a fast cure profile in an epoxy composition which comprises heating and curing an epoxy composition of claim 1 in which the difference between the beginning (Ti) and end (Tf) of the exotherm is less than 70° C. as determined by DSC analysis.
7. A curable epoxy composition comprising the contact product of at least one epoxy resin and an epoxy curing agent comprising an imidazole-isocyanate adduct which comprises a reaction product of at least one imidazole, at least one diamine, and at least one member selected from the group consisting of at least one polymethylene diisocyanate having 2-8 methylene units and at least one polymethylene poly(phenylisocyanate); wherein the imidazole-isocyanate adduct comprises an adduct represented by formula:
wherein x=1-10, y=1-10, l is 2-10, m is 2-8 n is 3-8, q is 2-10, and R1, R2 and R3 independently represent hydrogen, C1-C20 linear or branched alkyl, C6-C10 aryl, alkylaryl or arylalkyl; or C5-C6 cycloaliphatic.
8. A curable epoxy composition comprising the contact product of at least one epoxy resin and an epoxy curing agent comprising an imidazole-isocyanate adduct which comprises a reaction product of at least one imidazole, at least one diamine, and at least one member selected from the group consisting of at least one polymethylene diisocyanate having 2-8 methylene units and at least one polymethylene poly(phenylisocyanate); wherein the imidazole-isocyanate adduct comprises an adduct represented by formula:
wherein x=1-10, y=1, l is 2-10, n is 3-8, q is 2-10, R is (CH 2 ) m and m is 2-8 or the polyvalent residue of polymethylene poly(phenylisocyanate) having an isocyanate functionality of 2.1-3.5; and R1, R2 and R3 independently represent hydrogen, C1-C20 linear or branched alkyl, C6-C10 aryl, alkylaryl or arylalkyl; or C5-C6 cycloaliphatic.
9. A curable epoxy composition comprising the contact product of at least one epoxy resin and an epoxy curing agent comprising an imidazole-isocyanate adduct which comprises a reaction product of at least one imidazole, at least one diamine, and at least one member selected from the group consisting of at least one polymethylene diisocyanate having 2-8 methylene units and at least one polymethylene poly(phenylisocyanate); wherein the diamine comprises 1,6-hexanediamine.
10. A curable epoxy composition comprising the contact product of at least one epoxy resin and an epoxy curing agent comprising an imidazole-isocyanate adduct which comprises a reaction product of at least one imidazole, at least one diamine, and at least one member selected from the group consisting of at least one polymethylene diisocyanate having 2-8 methylene units and at least one polymethylene poly(phenylisocyanate); wherein the diamine comprises 1,4-butanediamine.
11. A curable epoxy composition comprising the contact product of at least one epoxy resin and an epoxy curing agent comprising an imidazole-isocyanate adduct which comprises a reaction product of at least one imidazole, at least one diamine, and at least one member selected from the group consisting of at least one polymethylene diisocyanate having 2-8 methylene units and at least one polymethylene poly(phenylisocyanate); wherein the member comprises polymethylene poly(phenylisocyanate) having an isocyanate functionality of 2.1-3.5.